Edward Steinfeld and G. Scott Danford
The Center for Inclusive Design and Environmental Access
School of Architecture and Planning SUNY/Buffalo
October 25,1993

Abstract

This article reports on research completed as part of a contract from
the U.S. Architectural and Transportation Barriers Compliance Board.
The goals of the project were to complete a state of the art review
on the subject of automated doors and develop recommendations for revising
the ADA Accessibility Guidelines(ADAAG) in light of the findings. These
recommendations address both scoping criteria when and if automated
doors should be required, and technical criteria how they should be
designed if they are used in buildings. The article summarizes the findings
of the research and the recommendations.

Introduction

From the "Flash Gordon" serials in the '50's to Star Trek,
the Next Generation, theautomated door is a ubiquitous element in science
fiction. Yet, after 40 years of imagery, life still has not imitated
art. The automated door has yet to become universal.

Automation is generally reserved for two purposes,
accommodating high flows of pedestrian traffic and providing accessibility
for people with disabilities. The main source of technical design criteria
for accessibility is ANSI A117.1 (1986) Standard, Making Buildings and
Facilities Accessible to and Usable by People with Disabilities. This
voluntary standard is currently referenced directly or indirectly by
many state accessibility codes. The standard includes maximum values
for the opening resistance force for manual doors. A door that has greater
opening resistance must be automated. Existing human factors research
indicates that many people with disabilities cannot open doors with
resistive forces as low as those specified in ANSI A117.1(1986). Yet,
these requirements have been a source of concern for closer manufacturers,
architects and code officials for many years who believe that the criteria
are too stringent and lead to situations where doors will not close
properly. In fact, the Uniform Federal Accessibility Standard (UFAS),
the regulations for the Americans with Disabilities Act(ADA) and ANSI
A117.1 all omitted requirements for maximum opening force at exterior
doors.

The ADA greatly expanded the legal mandate for improved building access.
As regulations for the Act were being developed, people with disabilities
identified the need for improved accessibility to doors as a major problem.
Allowing higher resistance forces for manual doors while, at the e same
time, requiring automated doors, could overcome industry objections
to low opening resistance and address the accessibility concerns as
well. In fact, several states have already adopted provisions that mandate
automated doors in certain situations. Yet others have increased the
maximum limit for opening resistance without requiring automated doors.

There is another important argument for giving more attention to automated
doors. The concept of "universal design" has become the focus
of accessibility in the '90's. Universal design means design that accommodates
all people, not only people with disabilities. It includes design that
will assist the elderly, children, pregnant women, people carrying packages,
etc. Automated doors are a perfect example of universal design. Everyone,
even the crew of the Starship Enterprise, benefits from the added convenience
they provide. With the advent of the ADA, we can expect that the use
of automated door products will increase, even if the federal regulations
do not currently mandate their use. The time has come to give this product
more attention in design practice.Human Factors of Door Use

Door use can be described as a process which includes seven subtasks:

1. Perceiving and understanding door operation
2. Altering gait, adjusting body posture and maneuvering within reach
3. Reaching and grasping handles, switches or locks
4. Applying force to overcome resistance of handles, switches or locks
5. Applying force to overcome resistance of the door, mechanical door
closers and pressure differentials
6. Passing through the doorway, including making adjustments in posture
and continuing to apply force
7 . Closing the door and locking it by repeating tasks one through five
above on the other side of the door.

The abilities of the person, the ambient environment
and the social context play a major role in successful completion of
the task. These factors can affect the perception and understanding
of door use as well as the level of stress involved in the task. Stress
may be related to limitations in ability, difficult environmental conditions
such as low levels of illumination or social pressures such as a crowd
of hurrying people. Automating doors is a means to reduce the stress
of door use. Automated doors are specifically designed to reduce congestion
and increase access, but they also can be helpful to control access
and improve security. Although automated doors can reduce accidents,
their mechanical operation, which is outside the control of the individual
user, also can create potential safety problems. Door use is a critical
aspect of safe egress from buildings in emergency situations. Building
safety codes and standards reflect this fact through many detailed design
criteria. However, during power failures the automatic features may
be disabled. Thus, automated doors must be designed to address these
emergency concerns if they are part of designated exits.

For people with disabilities, difficulties with door use are more pronounced
and often a stressful aspect of everyday experience. Automated doors
can make the door use easier. But, as the analysis and model above make
clear, many human factors issues that should be addressed in the design
of automated door systems. Although much research has been completed
about door use, little research has been completed specifically on automated
doors. The model of door use can be useful to summarize what we do know
and identify the research gaps.

From existing research, we know that understanding the operation of
automated doors can be a problem for people with disabilities and the
elderly. We do not know how widespread the problem is since the existing
research has observations from only a few subjects. New and innovative
products, like automated revolving doors, seem to create the most serious
difficulties. Although existing safety standards require signage on
automated doors, we do not know if those provisions are adequate. Furthermore,
no research has been done on how information about door operation should
be conveyed to visually impaired individuals. Since people who cannot
see use their hands and canes to learn about the operation of doors
and devices they encounter, attention should also be given to safety
for tactile exploration.

Although considerable research has investigated the need for maneuvering
clearances in front of doors, no attention has been given to maneuvering
clearance necessary at power assisted doors.

There has been considerable research on the use of
handles, switches and locks by people with disabilities. This research
includes specific studies on card slots, push buttons, keys and other
devices that are used with locks. Often doors equipped with power operators
have high-tech security devices like card readers. There is information
on how to make such systems accessible.

From the perspective of accessibility, the specification of automated
doors is tied to the force required to open doors. If a door handle,
lock or door presents too great a resistive force for people with disabilities
to overcome, then an automated system can be specified to substitute.
Much research has been completed on the subject of opening doors against
the resistive forces of mechanical closers and air pressure differentials.
Although some of the findings are divergent, they can be explained by
differences in research methods and sample selection. Given the purpose
and intent of an application, it is possible to use the existing data
base to make appropriate recommendations for maximum resistance forces
(minimum opening forces) at manual doors.

Research indicates that the abilities of the more severely disabled
population to resist the forces of door closers are very limited. Closers
are not currently designed with a level of efficiency that would allow
all doors to close properly if the opening force were set at the limit
that this group of people could manage on an everyday basis. Furthermore,
many people with severe disabilities have limited use of their hands
and arms.

Only one study has been completed on emergency use of doors. When compared
to other studies, the findings indicate that, under emergency conditions,
people with disabilities can exert relatively high forces to overcome
the resistance of door closers. Larger opening forces may therefore
be possible for doors used only for emergency use or emergency modes
of automated doors.

Research has demonstrated that passing through doors against the resistance
of a closer is quite difficult for many people who use wheelchairs,
particularly children. The main problem seems to be that do or users
have to exert force to keep the door from closing while they are moving
through the opening. Safety issues for people who walk or wheel slowly
while using automated revolving doors are a special case of this problem.
These doors do not really "close". Thus, the user can be bumped
by the leaf behind them. Manufacturers have developed several different
approaches to this problem but none has been evaluated in depth.

The samples used in research on automated doors are not fully representative
of the disabled community. In particular, very few people with visual
impairments have been included. No research has been completed with
people who have developmental disabilities or hearing impairments. Field
studies have not been conducted with children. In the reports of field
research, differences between the people who used the door were not
examined in detail. Thus, we have limited information about the variation
in abilities among people with different types of disabilities.

The research that has been completed addresses many different types
of doors and related devices. However, there are some issues that have
only been studied with very small samples of individuals. In particular,
systematic variation of different door features on the same type of
door is lacking. The ambient environment has received practically no
attention. No research has been completed on the impact of differences
in illumination, particularly as it relates to signage. The impact of
wind and temperature has not been examined. The impact of crowding is
another neglected issue. Finally, little research has been completed
on the unique concerns of different building types.

Automated Door Products

Our product search identified 86 manufacturers of door-related products
not all of which necessarily make automated products. Letters of inquiry
were sent to all of the manufacturers with a request for information
on their automated door products, if they produced them. Of the 86 manufacturers,
all but 14 responded. Among these respondents, 18 identified themselves
as manufacturers of automated door products and sent catalogs on a total
of 121 different product lines including 42 activating devices, 40 operating
devices and 39 door systems.

Interviews with six manufacturers suggest that most product development
is focused on design improvements such as making the devices smaller
and less obtrusive, safer and more secure. In the accessibility area,
more attention is now being given to wireless remote activation devices.
Most companies that produce a large range of different products have
specialized devices for accessibility. Other companies specialize in
accessibility products only. Some products are specifically designed
to assist in converting existing manual doors to automated operation.

According to the manufacturers of manual door closers, identified a
key design problem is meeting the requirements of accessibility codes
that have limitations on the opening force of exterior doors. The physics
behind mechanical door closer design requires the opening force to exceed
the closing force. As individuals open the door, they transfer energy
to the door closer. The closer stores the energy (in a spring or other
device) until the door begins to close. The energy stored is then applied
to the door through a lever arm. The efficiency of this operation is
only about 60 percent. Thus, an 8.5 lbf. (37.8 N.) opening force(required
by some codes for exterior doors) translates into a 5 lbf. (22.2N.)
closing force. Manufacturers maintain that such a force is not sufficient
to overcome the resistance of door weight, HVAC pressures, wind, gasketing,
stiffness of latching mechanisms, installation tolerances, hinge friction,
etc. Another problem is that these requirements are difficult to enforce.
No one knows what the actual site conditions will be. Installation,
maintenance and wind behavior, among other considerations, play major
roles in determining the actual forces necessary to close the door as
well as the force of opening. Such factors cannot be predicted accurately
during the design and specification of products so a factor of safety
is needed to ensure proper performance.

The manufacturers also reported that designers (and
possibly code officials) have interpreted the existing codes to mean
that low energy and power assisted doors must comply with the manual
door opening force requirements so that they can be operated manually
when power fails. This results in the development of a product that
seems redundant. If a door meets opening force requirements, why would
a building owner want to pay extra to automate it? Only facilities that
seek ultimate convenience would install such systems.

The
market for automated doors is becoming more defined. The type of product
most appropriate for a particular application is determined by frequency
of operation, speed of operation required, new versus existing construction,
traffic flow and cost. Products are available to address the full range
of applications based on these factors.

Automated door systems include four sets of components: door and frame,
opening and closing hardware, operating controls and information display.

The door and frame used determine the clear width of the door and the
method of opening. Products are available to automate swinging, sliding,
folding and revolving doors. Both opening and closing functions can
be automated. Some automation products do both. Others only open the
door, relying on standard mechanical closers for the closing function.

Operating controls include switches that require deliberate actions
to engage the automated opening/closing device, floor mats that activate
a door when someone walks over them during their approach to the door,
and sensing systems that activate the door automatically when a person
comes within range (Fig. 1). Switches come in many different forms including
push buttons or plates, keyed locks, keypad locks and card readers.
Many products have remote control options that operate like garage door
openers or television remote controls. Additional operating controls
regulate the function of the door, depending on actions of the user.
The most common devices of this type are safety mats or sensors that
prevent the door from hitting a person as it opens. Security functions
can be automated as well through the use of an electric latch. The latch
may be controlled by the same switch as opening and closing functions,
or it may have separate controls.

Information displays are an important part of automated door systems.
If an automated door does not have any readily identifying characteristics
(e.g. floor mat) labeling should identify it. Without this labeling,
the user may be startled by the door when it opens or may not know how
to activate the automated features. When automated door systems require
specific actions to engage certain features, directions must be communicated
to the user. Safety warnings are also required to avoid accidents. For
example, one way doors should be labeled to avoid pedestrian collisions
in high traffic areas and ensure smooth traffic flow. The most sophisticated
doors have audible communication systems to convey operating and safety
information.

The availability of options in each component generates
a high degree of variability for door systems as a whole. Classification
is useful to help in selecting the best options for each application.
The most useful classification is based on the force produced by the
door as it opens. The industry has developed two voluntary standards
that distinguish "full powered" from "low energy"
and "power assist" doors. Full powered doors produce more
kinetic energy because they open faster. These doors should comply with
ANSI/BHMA A156.10. Low energy and power assist doors should comply with
ANSI/BHMA A156.19. Full powered doors have more stringent safety requirements.
Low energy doors cannot open faster than 3-5 seconds, depending on size
and weight. Full powered doors are designed for much more frequent use
than low energy doors. They are the type that is typically used at the
entries of supermarkets or transportation terminals. These doors always
have automated controls such as floor mats or sensing systems. Their
primary purpose is to allow a rapid flow of pedestrians. Low energy
and power assist doors, on the other hand, are designed for a lower
level of use. Their primary purpose is to provide accessibility for
people with disabilities and the elderly. They are usually activated
by push button or pad.

Full powered doors can only be used in automatic mode except during
emergency use. Some low energy doors, however, are de signed to be used
both in manual and in automated mode, at the convenience of the user.
These doors generally open slowly to preserve kinetic energy. Users
who do not want to wait for the door to open can open the door manually
and pass through at a higher rate of speed.

Power assist doors provide assistance to augment the user's application
of force. One type reduces the resistance of a manual closer so that
the door can be opened more easily. It complements the force of manual
operation and is activated automatically as a door begins the opening
cycle. This type of operator is used where doors would be difficult
for everyone to open and the power assist feature is needed all the
time. Power assist doors are often used in health care or industrial
facilities where people are carrying heavy loads through doorways. A
second type of power assist door is sometimes called "reduced effort."
doors. This type requires the deliberate activation of a switch to engage
the operator. The switch reduces the resistance the closer exerts against
opening. The switch is needed because such doors are designed for only
intermittent power assist use for those people who cannot manage the
door without it. The full force of the closer is automatically re-engaged
once someone has passed through the door. One product does this by supplying
compressed air to the closer. A compressed air system can provide power
assist to many doors from one compressor(Fig. 2).

The frequency of traffic at an entrance is not always
the major factor in determining the door type and level of automation.
Some automated door products are installed solely for convenience. For
example, automated folding doors may be used to temporarily partition
a space (Fig. 3). As an other example, low energy door systems are often
used at entrances that receive a high volume of use. Such entrances
would have many doors, one of which is a low energy door that provides
accessibility for people with disabilities (Fig. 4). This could be a
very appropriate solution where high traffic levels are intermittent,
for example, a performing arts facility.

Energy conservation is a major goal in the design of full powered automated
door systems. Heavily traffic entrances can be a source of significant
energy loss. Revolving doors are used to reduce energy expenditure.
Automated revolving doors are one of the newest automated door products.
Revolving doors are available in many sizes and configurations (Fig.
5) They can be much larger than manual revolving doors, large enough
to be accessible for people who have disabilities. These systems are
perhaps the most sophisticated of any automated door product. They can
have multiple speeds for different operating modes(standard use, slow
use and idle). Some have variable speed features that are automatically
adjusted. Sensing systems track the users and adjust the speed of the
door accordingly (Fig. 6).

Security is an important concern in the design and specification of
automated door systems. Full powered systems are simply turned off when
access is restricted. Manual keyed locks are then used to ensure that
they will not be pried open. Low powered doors can be locked manually
or have electric locking devices. Some automated doors are installed
in high security locations. Card readers and combination locks are used
to restrict access. In addition, automated revolving doors can be used
to trap people who try to enter a high security area and are not authorized
to do so. These doors only open enough to let a person pass into a compartment
of the door but not onto the other side. They rotate in two steps. If
an access code or card is not valid, the door will not complete the
cycle and trap the individual within the enclosure. Such doors are usually
not large enough to be accessible for people who use wheelchairs.

In contrast, manual emergency access is required at doorways that are
part oaf required means of egress. To ensure that automated doors will
be operable when the power is off, emergency use modes are designed
into the doors. Full powered doors have "break-out" features
that allow swinging doors to be pushed open in the direction of travel
free of control from the mechanical operator. Sliding automated doors
also have such features. The door panels pivot in their tracks upon
the application of force. Revolving doors are designed with wings that
fold back when enough pressure is applied so that users can walk freely
on both sides of the central hub. Low energy doors can usually be operated
manually even when the power is off. For locked doors, strikes can be
operated either electronically or by a manual exit device.

Accessibility regulations that limit the amount of
force allowed to open a door have generated a market for low energy
operators. Many of these products are sold as complete systems including
door, frame and operator. Other products are sometimes called "retrofit"
or "after market" operators. The operator is sold separately
and can be added to a door at a relatively low cost to provide a minimum
level of automation. The device is attached to the top of the door or
the door frame. It powers a lever arm that pushes the door open (Fig.
7). One United Kingdom company makes a very low cost product that attaches
to the bottom of the door. Upon activation, a small wheel in contact
with the floor turns and opens the door. This product is intended primarily
for residential applications(Fig. 8). The low cost of the after market
openers has made them attractive for application in new as well as existing
buildings.

Early automated door technology used pneumatic or hydraulic operators
coupled with swinging doors and floor mats. Technological innovations
have produce d a number of new products. One is the development of sliding
automated doors (Fig. 9). These doors can have single slide, bi-parting
or telescoping panels. A sliding door system takes up far less space
in the flow of traffic than a swinging door system and does not always
need guardrails. Perhaps the most significant innovation, however, is
the trend away from pneumatic and hydraulic operators to electro-mechanical
devices. The latter have a lower initial cost and require less maintenance.
The most significant innovation in operating controls is the development
of sensing systems that pick up the movement of pedestrians without
the need for floor mats. A common sensing system is a motion detector
(using infrared, microwave, radio frequencies or ultrasound) mounted
above the door opening (Fig. 10). The range and pattern of the detection
area can be adjusted to accommodate different needs, surroundings and
patterns of pedestrian use (Fig. 11). Presence sensors are relatively
new devices. They can detect both moving and stationary objects (Fig.
12).

New technology entering the market makes use of microprocessors to provide
more sophisticated control of door function. Such control allows the
door speed and direction to be adjusted automatically in response to
conditions encountered during the door's movement. One useful new feature
is "safety stop and reverse". A microprocessor stops the door
and reverses the direction if a force is encountered as the door is
cycling open or closed. More sophisticated control can include distinguishing
between a force applied to the door by an inanimate object or a force
applied by a person. Macroprocessor control provides new ways to convey
information to door users, feedback that can help them negotiate the
door with less stress and increased safety. For example, a presence
sensor can detect a person that has stopped in the middle of the passage
and send a signal to the microprocessor control. The microprocessor
evaluates the data and then activates a gentle prerecorded announcement
to encourage the individual to proceed. This level of technology promises
to make the use of automated doors a highly interactive process with
many options for controlling use of the door in response to different
conditions and patterns of use. It presents many advantages for energy
conservation, security and accessibility.

The rehabilitation engineering field has also been
active in devising both low-tech and hi-tech approaches to automating
doors albeit from a different point of view. Rehabilitation engineers
develop technology to assist people with disabilities to be more independent.
Much of their work is custom design and construction for individual
clients. Since automated door systems cost at least $800, rehabilitation
engineers have devised several inexpensive ways to automate existing
manual doors using off the shelf products. One team of engineers, as
a student project, adapted a small compressor and linear actuators to
open a door and latch on a residential door. It was activated by a standard
garage door remote control (Fig. 13). Devices like these often find
their way eventually into the marketplace as new products. A good example
is the powered door wheel described above.

On the hi-tech side, rehabilitation engineers have developed "environmental
control systems" (ECS) to help people with very severe disabilities
use equipment in their homes or workplaces. Computers with sophisticated
"no hands" interfaces are the heart of such systems. People
who have no use of their hands access the computer using chin controllers,
"sip and puff" devices, eye-gaze interfaces or speech recognition
systems. Any device that can be controlled by an electrical signal can
be connected to the system. Remote control devices can also be used
to eliminate costly wiring. Automated doors are often a part of environmental
control systems.

A new trend in design of ECS is integration with electric wheelchairs.
Many people use the same types of controls for both computer systems
and wheelchairs. Many electric wheelchairs have on-board microprocessors
that are powerful enough to do many things in addition to controlling
the wheelchair. By integrating ECS with electric wheelchairs, the number
of devices necessary for independence is reduced, and the ECS can become
portable so that it can give access to many devices outside the home.
The development of ECS is important for the future of low energy automated
doors because compatibility between the two systems would make doors
accessible to people who currently cannot activate manual switches.
It also suggests the possibility of more flexible door security in housing
for people with disabilities. Current systems, for example, are not
accessible for remote control use if they are locked with a keyed switch
at night. Some companies offer remote control, but a separate transmitter
is needed for each door. Where several doors are close together a remote
signal could inadvertently activate all of them at once. Wheelchair-integrated
ECS provides the flexibility and power needed to program a variety of
signals for each person all controlled by the same device an individual
uses for other environmental control functions.

Regulations and Standards

Building regulations at local, state and federal levels have requirements
for making doors accessible. The two key federal regulations are the
ADA Accessibility Guidelines (ADAAG) and the Uniform Federal Accessibility
Standard (UFAS). These are both based in large part on the technical
criteria in the national voluntary consensus standard, ANSI A117.1.
A new version of the ANSI A117.1 standard has recently been approved
(1992). The requirements related to doors in all these documents were
identified and compared. There are few differences between them.

The accessibility requirements of state codes vary from state to state.
Some states have adopted ANSI A117.1, ADAAG, UFAS or model building
code requirements, all of which are relatively similar. Another group
includes states that rely on one or another of these source as a basis
but that have not adopted them by reference. A third, smaller group
have their own codes. Only six states have door design criteria that
differ from ADAAG. One state, Wisconsin, recommends the use of automated
doors where exterior doors have resisting forces greater than 8lbf (35.6N).
Two states, Massachusetts and New Hampshire, require "compensating
devices" at exterior doors with resistive forces exceeding 15 lbf
(66.6N) and interior doors exceeding 8 lbf (35.6N). The states of Michigan
and Connecticut require that at least one entrance to certain types
of buildings have automated doors. The State of Washington recently
enacted a change that requires all automated doors to stop and re-open
automatically if they encounter a body or object in their path.

Of the 12 Canadian provinces and territories, all have either adopted
or adapted the Canadian National Building Code. This Code requires at
least one automated door for certain types of buildings.

Facility Management

We completed a survey of ten organizations whose facilities are equipped
with automated doors. This survey was completed in two metropolitan
areas, Buffalo, NY. and Washington, DC. The survey provided insight
into issues related to design, installation and use of automated door
systems. All the organizations surveyed were generally satisfied with
the products that they were using. There were few complaints about the
door systems. They are also satisfied with the acquisition costs. Durability,
ease of installation, ease of repair, safety and security do not appear
to be significant factors in decision making about automated door systems.
Energy conservation is a major concern in the use of automated door
systems. However, it is basically a function of high traffic that leads
to the need for such systems. Many installations in cold climates use
vestibules to reduce heat loss in winter.

In general, the selection of a particular automated door system is based
on reliability and durability rather then cost. Once the level of reliability
and durability is established, cost then becomes an issue for competing
systems of the same type.

Wind loads and pressure differentials, both positive and negative, are
design concerns that must be overcome in all exterior door design. In
addition to automation, back-checking devices can be added to reduce
damage caused by wind. Energy conservation can be addressed through
timing of automated doors, and use of revolving doors, vestibules and
air curtains.

High prevailing winds can affect the performance of all types of automated
doors. Sliding doors are particularly affected. High winds blowing perpendicular
to the doors have a significant impact on the performance of the doors.
Yet only a few of the facility managers interviewed reported problems
with high winds. This is probably because it is a known factor and is
considered in the selection and design of door entries. Where problems
exist, corrective action is taken.

Control mats can be affected by moisture. Snow, ice or heavy rainfall
leads to moisture accumulation underneath mats and failure of door controls.
Corrosion problems can develop in control mats caused by salt used to
melt ice on the sidewalks outside. Cold weather causes slow operation
of exterior pneumatic door operators. In response to such problems,
several facility managers in our survey indicated their organizations
had abandoned control mats for motion detectors or other sensing systems.

The facility managers surveyed were satisfied with the purchase cost
of automated doors and generally with the cost of maintenance. Swinging
doors are less costly then sliding doors. In general, the cost of operating
the doors themselves is low. The principle operating cost associated
with automated door is due to increased HVAC loads caused when the doors
are open frequently. Also additional space such as vestibules or equipment
such as air curtains are often needed to alleviate such problems in
installations with high traffic. However, the same costs would accrue
with manual doors. There are significant maintenance costs associated
with door equipment. One organization reported the need to periodically
adjust motion detectors. Vandals push them out of alignment. Another
facility manager reported that their company (a large supermarket chain)
has a full-time position devoted to door maintenance. This individual
continually visits stores and makes necessary adjustments and preventative
maintenance. Most organizations contacted have a service contract to
maintain the doors in working order. In general, the organizations surveyed
were satisfied with the physical safety and security of automated door
products for public use under general operating conditions. Only a few
minor security problems were mentioned related to vandalism. There were
some serious safety problems reported, however. It was noted that children
can slip under the guardrails and step on control mats causing the door
to open. The two supermarket chains with large numbers of doors both
reported incidents. One had a number of incidents in which doors closed
on the fingers of small children who inserted them along the hinged
edge of the door. They now have installed guards along the hinge to
prevent the doors from closing when an object is detected along that
edge.

Most Facility Managers are happy with the performance
of their automated doors. They are generally considered very reliable.
They do report that hydraulic units require more maintenance. Most report
that they have been switching from hydraulic systems to electro-mechanical
systems . Electro-mechanical doors seem to be more reliable and require
less maintenance. One organization (a university) reported that they
selected sliding doors over swinging doors due to their ease of repair
and reliability. For low cost installations they use swinging doors
and maintain them with their own staff. There is a move away from control
mats to motion detectors or other sensing systems because of the failures
caused by moisture on the mats and the availability of low cost, easily
installed, reliable electronic sensing systems. Motion detectors created
unanticipated problems for several organizations. They report that pedestrians
walking across the front of the opening and even cabs in the loading
zone triggered the detector. These problems can be alleviated by adjustments
of detection areas. In new buildings, location and orientation of doors
can solve the problem without resorting to a smaller detection area.

At least six to eight years of trouble-free operation can be expected
from new installations according to our respondents. One organization
argued that routine maintenance can extend the length of trouble-free
operation to 20 years, seven for pneumatic and hydraulic door systems.
They suggested that reports of dissatisfaction are due to absence or
inattention to scheduled maintenance programs.

None of the organizations in our facility management survey reported
a problem with emergency operation. On the other hand, several seem
to have never considered the issue in the past. A few facility managers
were prompted by our interview to wonder how their doors would perform
in an emergency. They specifically voiced concern about the effect of
smoke on motion detectors and infrared detectors.

As indicated above,energy losses due to high volume
traffic are one of the most significant cost factors in the use of full
powered automated doors. Supermarket chains use large vestibules between
two sets of doors to help reduce energy losses. One organization said
that it had made a decision to utilize only revolving doors in an attempt
to cut energy costs. These doors cost from $40,000 to $100,000. This
commitment indicates the extent of the problem for that particular organization.
Low energy door installations do not cause as severe an energy problem
because they have less traffic. Although these doors may remain open
a long time, several people can pass through before they start closing.
This reduces the traffic at other doors.In general the most common types
of automated doors installed are swinging doors with electro-mechanical,
pneumatic or hydraulic operators. Low energy doors that are installed
primarily to facilitate accessibility for people with disabilities are
usually activated by a touch/pressures witch although some products
havea feature that activates power upon pushing the door.

Organizationsreported that once installed, automated doors tend to become
the preferredmeans of access for all users, not just people with disabilities.
Also,when these doors do not function up to 100% capability, the users
are quick to complain. This is in contrast to generally acceptable problems
that might be experienced with manual doors. One organization (a convention
center) reported that automatic doors installed foraccessibility purposes
were the most popular for building users.

Automated doors can improve accessibility significantly to the point
that all building users notice. But, existing buildings do present some
difficulties. Historic preservation presents a dilemma. Automatic doors
were used in few historic buildings. The technology is too new. Products
that do not attach permanently to the door have some benefit with respect
to historic preservation concerns. Apparently this is more acceptable
than permanent alterations, even though the door opener is still a visual
intrusion. Some minor problems fitting automated door systems into existing
buildings were reported. A major federal performing arts facility in
Washington, DC had custom designed doors with high quality finishes
with a bronze and white color motif. New automated door systems installed
in the building were anodized aluminum and clashed with the existing
aesthetics. A school district reported that an unanticipated cost for
their installation was due to the difficult wall patching and electrical
costs related to installing a vandal proof switch in a masonry wall.

Recommendations

The performance specifications below summarize the recommendations for
automatic doors that were developed based on this research. Detailed
technical design criteria and rationales were included in the final
report of the project which is available from the U.S. Architectural
and Transportation Barriers Compliance Board.

1. Required Automated Doors: All new buildings used by the public should
have at least one automated door at accessible entrances. There should
be an exception for small buildings where adding such a door may be
a financial hardship for building owners.
2. Automated Revolving Doors: Automated revolving doors should be allowed
at accessible routes. Where automated revolving doors are used at an
accessible entrance, an alternative accessible swing or sliding door
should also be available at the entrance or the revolving doors should
have safety systems that stop the door without contacting a stationary
person or an object in its path.
3. Remote Controls: Remote controls, keyed switches, card readers or
combination switchesshould not be the sole means of control for automated
doors during normal hours of building operation. They could be the sole
means of control at employee entrances or during times when the public
is not provided access to the building.
4. Door Width: Automated doors must be wide enough for use with wheeled
mobility devices and walking aids. Full powered or low energy bi-parting
and telescoping doors should be allowed to meet this requirement based
on the width of the entire opening rather than only one door leaf.
5. Thresholds and Edges: Thresholds and control mats at automated doors
should not have abrupt edges that would pose a barrier or safety hazard
to persons who use wheeled mobility devices, walking aids or to persons
who have visual impairment.
6. Maneuvering Space: There should be enough maneuvering space in front
of automated doors and controls to accommodate use of wheeled mobility
devices. Accessible automated revolving doors should have enough space
within them for a person in a wheelchair and an attendant.
7. Door Timing: Automated doors should remain open long enough to allow
people who have limitations in gait to enter the opening and pass through
the door.
8. Opening Force: The force required to open a manual door should be
limited. Above this limit, doors should be automatic. The force required
to open an automated door in an emergency, when power is off should
also be limited. These limits should not hamper the ability of a manual
door to close properly in adverse conditions.
9. Bump Force: The force induced by a low energy door should be limited
to avoid knocking an individual off balance. Three options should be
considered: a maximum force threshold, sensor controlled variable forces
and safety systems that prevent contact.
10 Door Swing: Full powered doors that swing against the direction of
travel should have protective features to ensure that they will not
hit someone approaching the door.
11. Activating Controls: Control switches should be easy to use by people
that have difficulty forming a grip.
12. Activation Forces: Forces necessary to operate door controls should
be within the limits of severely disabled people to manage.
13. Control Location: Switches for operating low energy automated doors
should be located as follows:
a.within the reach range of people with severe disabilities
who use wheeled mobility devices
b. where access to the door is convenient after use
c. in close proximity to the door
d. in standardlocations
e. not on the door itself
14. Detection Zone: Sensors and control mat at the pull side of hinged
doors should detect people approaching doors early enough to ensure
that the door will open before the user reaches the sweep area.
15. Visual Instructions and Warnings: Warning signs should be provided
for all automated doors except power assist doors. Instructional signage
should be provided for all automated doors. Both types of signs should
be in highly visible locations, have easily noticed colors and be large
enough to be read by people with visual impairments. Switches for low
energy automated doors should be identified with the International Symbol
of Accessibility.
16. Ground and Floor Surfaces: Floor and ground surfaces in the maneuvering
clearances and at the control location should not have a slope exceeding
the minimum required for drainage.
17. Background Noise: If audible warnings and messages are provided
to ensure proper operation of automated door systems, then they should
be distinguishable against the ambient background noise and be accompanied
by visual warnings or instruction labels.

Epilogue

Just as the first accessible standards limiting door opening resistance
spurred the generation of new low-cost automated door products, it is
hoped that implementation of these recommendations will lead toward
doors that truly meet the goals of universal design. Life can imitate
art if we have the commitment and use our creativity in the real world
as well as in the realm of imagination.

Disclaimer

The research and publication of this report were made possible through
a research contract from the U.S. Department of Education Contract No.
QA92005001. The contents of this report do not necessarily reflect the
view of the Department or the U.S. Access Board.Authors

Edward Steinfeld, Arch.D. is a registered architect
and a Professor of Architecture and Director of the Adaptive Environments
Laboratory. He is internationally known for his research on issues of
accessibility and universal design.

G. Scott Danford, Ph.D. is an environmental psychologist
and an Associate Professor of Architecture. His specialty is research
and systems development in facilities management with a focus on aging
and rehabilitation .